Poorer ablation outcome associated with elevated CRP
TAIPEI, TAIWAN. An elevated blood serum level of C-reactive protein (CRP) is an indicator of systemic inflammation and is associated with an increased risk of cardiovascular disease and atrial fibrillation. There is also evidence that an elevated CRP level is associated with a greater risk of afib recurrence after electrical cardioversion. Now Dr. Shih-Ann Chen and colleagues at the Taipei Veterans General Hospital report that an elevated CRP level prior to catheter ablation for AF is associated with a greater risk of failure.

Their study involved 107 patients with paroxysmal afib and 30 patients with persistent or permanent (non-paroxysmal) afib. The majority of the group (69%) had lone atrial fibrillation (LAF) and the average age of the patients was 54 years. All study participants underwent a circumferential pulmonary vein isolation (PVI) procedure with additional linear lesions as required using a NavX system for guidance. After the procedure all patients were prescribed amiodarone for 8 weeks and underwent examination every 1 to 3 months thereafter. After a median follow-up of 15 months, 91% of patients were in sinus rhythm following one or more procedures.

The researchers divided the patients into two groups depending on their pre-ablation CRP level. Group 1 (low CRP) involved 105 patients with a median CRP of 0.8 mg/L, while group 2 consisted of the remaining 32 patients with a median CRP of 5.6 mg/L. They found that the success rate for the initial procedure was 72% in group 1 and 50% in group 2. Corresponding numbers for final success rates were 94% versus 81%. Repeat rates in the two groups were 19% and 56% respectively. The number of ectopic-producing sites located outside the pulmonary veins were significantly higher in group 2 than in group 1 (34% vs 17%) supporting the notion that inflammation involving the atrial wall plays a significant role in AF – particularly in that of persistent and permanent AF.

There was a trend for the prevalence of hypertension and heart disease to be higher in group 2. The researchers also noted that patients with a high CRP level had higher glucose and glycated hemoglobin levels compared to those with lower CRP levels. They conclude that pre-procedure CRP level is an important predictor of the long-term success of catheter ablation and suggest that a level above 2.92 mg/L is associated with a significantly increased risk of failure.

Lin, YJ, et al. Prognostic implications of the high-sensitive C-reactive protein in the catheter ablation of atrial fibrillation. American Journal of Cardiology, Vol. 105, No. 4, February 15, 2010, pp. 495-501

Editor's comment: This study adds to the evidence that inflammation is involved in atrial fibrillation, particularly in the case of persistent and permanent afib. It also emphasizes the importance of having an hs-CRP test to determine if systemic inflammation is present and, if necessary, to deal with it prior to catheter ablation.